1. Field of the Invention
The present invention relates to a die assembly for riveting, and particularly to a die assembly which can firmly and automatically rivet.
2. Related Art
FIG. 6 shows a conventional die assembly 10 for riveting which requires manual operation. The die assembly 10 includes an upper die 101, and a base die 105. A fixing block 102 is mounted to the upper die 101, corresponding to a sizing block 103 which is mounted to the base die 105. A pair of clamps 106 is positioned at opposite sides of the sizing block 103. A workpiece (not shown) is placed onto the sizing block 103. When power is turned on, the upper die 101 moves downwardly, and the fixing block 102 forces the workpiece against the sizing block 103. Then the clamps 106 rivet the workpiece. The clamps 106 are then pulled away from the workpiece, and the workpiece is unloaded from the die assembly 10.
Placing, riveting, and unloading the workpiece are all required to be done manually. Riveting requires an operator to use both hands. The procedure is labor-intensive and unduly inefficient, which results in high manufacturing costs. Moreover, manual riveting limits the amount of pressing force which can be applied. Rivets are too often not firmly secured.
Therefore an improved die assembly for riveting is desired to overcome the above-mentioned shortcomings of the related art.
Accordingly, an object of the present invention is to provide a die assembly for riveting which has a high level of automation.
Another object of the present invention is to provide a die assembly which can firmly rivet workpieces together.
To achieve the above-mentioned objects, a die assembly for riveting comprises an upper die, a base die, a pair of clamps, and a pair of springs. The upper die comprises a fixing block, and a pair of pressing protrusions at opposite sides of the fixing block. A first slanted surface is formed at an end of each pressing protrusion. The base die comprises a sizing block to position a workpiece. Two supporting blocks are formed at opposite sides of the sizing block, each defining a through hole for accommodating the clamp. Two positioning blocks are formed at opposite sides of the supporting blocks. Each clamp comprises an end block having a second slanted surface corresponding to the first slanted surface of the pressing protrusion, and a connecting portion slidable in the through hole of the supporting block. The springs connect the clamps to the positioning blocks.
Other objects, advantages and novel features of the present invention will be drawn from the following detailed embodiments of the present invention with attached drawings, in which: